Well, it’s one thing to say that everyone sounds sucky at first, and that’s probably a universal truth in anything, but there are always reasons for it, and if there is a reason for something, there is something that can be done about it.
Being discouraged over it is not particularly constructive, so I prefer to take a more pragmatic approach. There is a reason I sound sucky, and if there is a reason for it, I can do something to eliminate it.
I think there may be two factors which interfere with and degrade the quality of our “listening experience,” i.e., make us think out playing sounds sucky.
When you are playing, a good bit of the sound you hear is transmitted to your ears through the bones in your head. What you hear is therefore more resonant, more vibrant, and more “full” than what someone several meters away will hear. (This is why our own voice sounds deeper to us than it does to others.)
If you are playing the piano or even a guitar, what you hear is more like what others hear, so you are able to shape the sounds more easily. It sounds the same to you as it does to others, so if your music is sounding good to you, it is sounding good to others. What you hear is what they get. There is a direct correlation between what you do and what they hear. That is, if you apply x amount of pressure to a piano key, y amount of sound is produced, and if you hear it as y, then everybody else does, too.
With whistle, you blow with x amount of effort/technique so that you hear y amount of sound, but everybody else hears half of that. You, therefore, have to play with 2x amount of effort/technique in order that everybody hears y. And you may need earplugs.
When you learn whistle, you will be emulating other players and trying to approximate what they are doing. You aim to produce the same sound, but you don’t realize that what YOU hear from yourself is not what others hear. The experienced player you are emulating did not himself hear it the way YOU heard him play–he heard MORE sound than you did. So, when you play, you produce the same sound he did TO YOUR OWN EARS, but it’s still “too thin” when others hear it–they’re not hearing all that you heard through your jaw.
It may be that one thing you have to learn in playing whistle and flute is to overplay somewhat, as far as what you hear, so that others hear a “full” sound. This is probably one of the good points to having a teacher . . . they probably coach adequate sound production right off.
So, what can you do about this if you don’t have someone handy to listen and provide advice??? A guy who works down the hall from me has a recording studio. I brought him the graphic of a clip and asked him about the big gaps between notes. He suggested to work on closing them up, but to do so by filling them with sound, not by “speeding up.”
When I tried that, I felt as though I were playing too loudly and overdoing it. I found myself becoming nervous that someone would hear me, and I realized that I was holding back for fear of bothering the neighbors. It sounded TOO LOUD to me, but someone sitting there with me said it wasn’t loud at all. So, I learned that I have to really blast away in order to get enough sound to fill up those gaps. (I also have to not come to a dead stop in between the notes. 
) And even when I’m blasting away to my own ears, it’s still not all that loud.
He also said that a lot of the gaps and tinny sound had to do with the recording apparatus. If the microphone isn’t sensitive enough to pick up all of the sound, you won’t actually record all the sound you produce. There actually is sound in those gaps, but the mike isn’t hearing it. With my cheapie mike, I have to be right up against it–literally an inch away–or it won’t pick up much at all.
When you hear CDs, you’re not always hearing raw sound. It’s been electronically enhanced. So, you may be attempting to sound like the impossible.
In the light of all this, you should feel better about the way you sound. Instead of feeling discouraged, recognize that the recording isn’t necessarily a truthful representation of what others hear.
Recognize that you’ve probably been accurate in YOUR hearing of your playing (since your jawbone has conducted it straight into your ears), but that you need to add sound and play even louder and more vibrantly in order to produce enough sound that others hear it the way you want them to.
So, it’s not that you still sound terrible! You have learned and improved to the point that you can play and sound good to yourself, and your ears aren’t lying to you. You’re hearing what you are playing! You’re just hearing more of it than they are.
The goal now becomes using those ghastly recordings to determine how much more sound you need to produce so that others can hear you, too!
Disclaimer: This suggestion was provide by a beginner AND truly sucky player!
) and even made a little breakthrough on Drops of Brandy today.